A numerical model for calculations of population inversions formed in the channels of CW gas-dynamic lasers

A theoretical model of population-inversion formation by means of rapid expansion of a previously heated mixture of CO ₂ and Ar is described. Various admissible radiative transitions between CO ₂ levels comprised in coupled v₁ and v₂ modes are considered without any assumption as to the form of the vibrational energy distribution. The resulting kinetic equations have been integrated together with gas-dynamic ones. The vibrational energy exchange and relaxation processes are treated according to SSH theory. The calculations presented here have permitted the checking of the assumption that the vibrational energy remains frozen and can be neglected in the gas-dynamic equations that describe the flow in supersonic nozzles for the relative concentration of CO ₂, ξ _{CO 2} ≲ 0.1.